DD- Virology of influenza Flashcards
An infectious disease caused by the influenza virus. The most common symptoms include: a high fever, runny nose, sore throat, muscle pains, headache, coughing, and feeling tired.
The flu
Persons _________of age account for more than 90% of deaths from the Flu
> 65 years
Influenza cases peak during the ______season
winter/spring
Influenza virus is an______virus with a segmented genome
RNA
Its genome is made up of 8 different pieces of single-stranded RNA, which encode several different viral proteins
Surrounding the core of influenza is a lipid envelope, with a lining of ______on the inner side of the envelope.
matrix protein
Two of the best characterized_________are the hemagglutinin (H) and neuraminidase (N) glycoproteins.
flu viral proteins
Influenza viral subtypes are identified by the combination of________on the viral coat (e.g. H1N1, H3N2 etc).
H and N proteins
There are 3 types of influenza virus.
Type A and Type B strains circulate in the population every year.
Type C strains cause__________
mild or clinically-insignificant illness
Type A strains are the cause of both epidemics and pandemics. Type A strains can infect__________
other animals
Two of the best characterized flu viral proteins are the_________ and neuraminidase (N) glycoproteins.
hemagglutinin (H)
*Both hemagglutinin and neuraminidase are surface proteins.
Hemagglutinin (HA) is involved in
- cell entry
Neuraminidase (NA) is involved in:
cell escape
There are 3 types of influenza virus.
Type A and Type B strains_________
Type C strains cause mild or clinically-insignificant illness
circulate in the population every year.
Two of the best characterized flu viral proteins are the hemagglutinin (H) and __________
neuraminidase (N) glycoproteins.
*Both hemagglutinin and neuraminidase are surface proteins.
Influenza binds _______ to enter cell
sialic acid
Common in lungs
Potentially severe illness:
Epidemics and pandemics
Rapidly changing
Birds, swine, dogs, cats, horses, seals, whales, humans
Type A Influenza
RNA virus are sloppy when they replicate leading to many:
mutations
Usually less severe illness
Epidemics, no pandemics
More uniform
Humans
Type B Influenza
Type A Name example:
A/California/7/2009 (H1N1)
a- Virus type California- Geographic origin 7- Strain number 2009- year of isolation (H1N1)- subtype
Antigenic Drift
a mechanism for variation in viruses that involves the accumulation of mutations within the genes that code for antibody-binding sites.
Antigenic Drift in flu virus can affect________ to stop AB binding
Hemagglutinin
Antigenic Shift is in _____ only
Type A
Major change, new subtype
Caused by exchange of gene segments
May result in pandemic
Antigenic SHIFT
Minor change, same subtype
Caused by point mutations in gene
May result in epidemic
Antigenic DRIFT
Transmission of Influenza
Droplet spread- Small particle aerosols
Influenza is transmitted primarily by the ________route
respiratory
Signs and symptoms of influenza in adolescents and adults
acute onset of fever, chills, myalgias, headache and cough
presentation tends to resemble that of bacterial sepsis, including lethargy, decreased eating and mottling
flu in neonates
tend to present with gastrointestinal symptoms (NVD); fever; anorexia; and various respiratory syndromes, including (croup), bronchiolitis, bronchitis and febrile convulsions
flu in Infants and toddlers
Major groups of Flu Rx
Matrix protein inhibitors
Neuraminidase Inhibitors
Matrix protein inhibitors:
Amantadine
Rimantadine
Only work on Influenza______subtypes
Type A
Neuraminidase Inhibitors:
Oseltamivir
Zanamivir
Peramivir (just approved 12/14)
Work on Influenza__________subtypes
types A and B
Matrix protein inhibitors
Work on?
M2 protein
a proton-selective ion channel protein, integral in the viral envelope of the influenza A virus.
Neuraminidase Inhibitors
works on?
preventing its reproduction by budding from the host cell.
block the neuraminidase enzyme
an influenza that reassorts in swine and then infects humans
Swine Influenza
ex: Pandemic H1N1
__________ were at exceptionally high risk for hospitalization and death if infected with Pandemic H1N1 (or any influenza)
Pregnant women
Infectious disease of birds caused by type A Influenza virus
Avian Influenza
There are 2 types of licensed seasonal influenza vaccines
iInactivated influenza vaccine (IIV)
Live attenuated influenza vaccine (LAIV)
this vaccine is an injectable, killed
vaccine; licensed for all individuals 6 months of age and older.
There are both trivalent and quadrivalent IIVs approved and available.
The quadrivalent is newer, but it will likely completely replace all trivalent vaccines. The additional strain is a second B virus.
Inactivated influenza vaccine (IIV)
Both influenza vaccines contain the same 3 strains of influenza and the ________ vaccines contain the same second B strain.
quadrivalent
this is delivered intranasally via a small, needle-free syringe that delivers a fine mist into the nose; licensed for healthy persons 2 yrs through 49 years of age. This contains the same influenza strains as IIV, however, it is only quadrivalent. An additional strain is a second B virus.
Live attenuated influenza vaccine (LAIV)
this is a live, attenuated (weakened strain) vaccine;
3 conditions must be met to declare a pandemic
1) Emergence of a new influenza virus subtype
2) Virus must infect humans and cause serious illness
3) Virus must have sustained transmission and spread easily among humans
Both inactivated and live vaccines are
reformulated annually to provide the best protection possible for what strains are
_________ to be circulating during the next season
anticipated
Intramuscular or intradermal
Trivalent and quadrivalent, moving toward all quadrivalent
Killed virus
Standard-dose and high-dose (HD for adults 65 and older)
Inactivated Vaccine (IIV)
Intranasal
Quadrivalent
Live
Live attenuated influenza vaccine (LAIV) (cold adapted, attenuated influenza vaccine)
50-70% effective among healthy persons <65 in well-matched years
30%-40% effective among frail elderly
Greater efficacy for prevention of hospitalization and death
Inactivated Vaccine (IIV)
Temperature-sensitive (do not replicate efficiently in lower airways)
Cold-adapted (replicate efficiently in upper airway)
Indicated for healthy 2-49 year olds
Live Attenuated Influenza Vaccine (LAIV)
Influenza Vaccine is Recommended for:
Everyone >6 months unless there is a contraindication to vaccination
